CASE REPORT
Aortic Root Re-replacement with Cryopreserved Aortic Homograft
in a Patient with Active Composite Valve-graft Endocarditis
Hideyuki Shimizu,1 Tatsuo Takahashi,1 Masataka Yamazaki,1 Naoki Hasegawa,2 Hankei Shin,3 and Ryohei Yozu1
1

Division of Cardiovascular Surgery, Department of Surgery, School of Medicine, Keio University, Tokyo, Japan
Division of Pulmonary Medicine, Department of Medicine, School of Medicine, Keio University, Tokyo, Japan3
Department of Cardiovascular Surgery, Tokyo Dental College Ichikawa General Hospital, Chiba, Japan

2(Received for publication on October 30, 2007)(Revised for publication on December 13, 2007)(Accepted for publication on February 21, 2008)

Abstract: We describe a repeat aortic root replacement using a cryopreserved aortic homograft in a patient with active composite valve-graft endocarditis and an aortic root abscess.
At the second surgery, infected prosthetic material was removed and surrounding tissue
was radically debrided. The cryopreserved aortic homograft was positioned using the fullroot technique with a concomitant coronary bypass graft. The postoperative course was uneventful and the patient continues to thrive 2 years after the repeat operation. (Keio J Med
57 (2) : 111－114, June 2008)
Key words: Allograft, Infective endocarditis, prosthetic valve endocarditis, Bentall operation, S. epidermidis

Introduction
Prosthetic valve endocarditis and re-operative aortic
root replacement are associated with high postoperative
mortality.1 Once an infected prosthesis becomes medically uncontrollable after aortic root replacement, the composite valve-graft must be removed and the aortic root
should be replaced once again. Operative mortality undersuch conditions can be extremely high. Homografts areconsidered to be the best graft for aortic valve reoperation to treat infected mechanical and bioprosthetic
valves, because the reported risk of developing early orlate postoperative recurrent infection is low and constant.
This apparently also applies to composite valve-graft endocarditis.
Case
A 56-year-old man developed palpitation for the firsttime after a cold in February 2005. He was diagnosed
with annulo-aortic ectasia with severe aortic regurgitation after a medical examination and referred to our hospital for surgery. The modified Bentall operation com-prising an implant of a composite woven Dacron prosthetic graft (28 mm in diameter) and a mechanical valve(23 mm in diameter) into the aortic root, re-anastomosing
the coronary ostia to the graft, and concomitantly placing
a saphenous vein graft from the aorta to the left anterior
descending (LAD) branch on May 16, 2005 was successful. The patient was discharged from hospital 25 days
later, but was soon readmitted with a high fever, bodytemperature, > 40.3°C, white blood cell (WBC) count,
16,400/mm3 and C-reactive protein (CRP), 8.39 mg/dl.
The body temperature and inflammatory reaction (C-reactive protein) promptly improved after starting empiric
antibiotic therapy with teicoplanin (TEIC) and meropenem trihydrate (MEPM). Six days later when methicillinresistant Staphylococcus aureus was defined as thepathogen of sepsis (Table 1), MEPM, which was administered mainly to combat gram-negative organisms, wasstopped. Therapy with TEIC was continued, the concentration of which was monitored once or twice each week
and the dose was adjusted to keep the trough between 10to 20 μg/ml. However, the infection was not completelycontrolled and worsened. We repeatedly detected S. epidermidis in blood specimens. Computed tomography

Corresponding Author: Hideyuki Shimizu, MD, PhD, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan, Tel: +81-3-3353-1211 (Ext. 62331), Fax:
+81-3-5379-3034, E-mail: hideyuki@sc.itc.keio.ac.jp
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Shimizu H, et al: Homograft for Active Composite Valve-graft Endocarditis

112

Table 1 Antibiotic susceptibility of pathogens obtained from patient’s blood
R, resistant; S, sensitive.
Antibiotics
PCG
MPIPC
ABPC
SBT/ABPC
CVA/AMPCCEZ
CTX
CPR

Sensitivity
RR
R
R
R
R
R
R

Antibiotics
CFPM
CDTR-PI
FMOX
IPM/CS
MEPM
VCM
TEIC
ABK

Fig. 1 Whole body CT shows abnormal fluid collection aroundcomposite valve-graft.

(CT) showed abnormal fluid collection around the graft(Figure 1). Transesophageal echocardiography (TEE) revealed a 15 × 5 mm mass at the aortic valve annulus anda soft tissue mass (abscess) around the graft. These findings indicated active infective endocarditis with a perigraft abscess. Coronary angiography showed excellent
patency of the saphenous vein graft to the LAD branch,which was achieved at the previous operation. The left
circumflex system was small. Gallium scintigraphy detected isotope accumulation at the site of fluid collection
around the graft and we determined periannular extension of the infection. The patient was scheduled for repeated surgery on July 16, 2005. The calculated logisticEuroSCORE,2 or the calculated predicted operative mortality for patients undergoing cardiac surgery, was28.55%.
Operative Procedures
The patient was placed in the supine position and thesternum was carefully entered through the midline using
an oscillating saw. The radial artery was harvested fromthe left forearm. Cardiopulmonary bypass was established using the superior and inferior vena cava for venous drainage and the femoral artery for arterial return.
The right upper pulmonary vein was cannulated for venting. A free radial arterial graft was anastomosed to rightSensitivity
R
R
R
R
R
S
S
S

Antibiotics
GMCAM
LVFX
LZD
QPR/DPRβ-lactamase

Sensitivity
R
R
R
S
S+

coronary artery #2 under beating. The previous graft tothe LAD was preserved. A purulent discharge was evident around the prosthetic graft. After aortic crossclamping, the ascending aorta was transected distal to thefelt strip which had previously been used for distal anastomosis. Carrel patches, or left and right coronary ostia,
were removed and the infected prosthetic material wascompletely removed. Perivascular malgranulation andsurrounding soft tissue were radically debrided. The operative field was washed with electrolytically-generated
water, then with saline, and the homograft was positioned. The fragile coronary buttons were ligated and theproximal end of the radial artery graft was sutured to thehomograft.
The patient was extubated on the 4th postoperative dayand TEIC was continued for 6 weeks postoperatively under therapeutic drug monitoring (TDM). During the first
3 days after the operation, cefazolin sodium (CEZ) andamikacin sulfate (AMK), which were routinely used during the cardiovascular surgery, were concomitantly administered. From postoperative days 10 to 31, biapenam
was added to TEIC because of a transiently re-elevatedWBC count. The postoperative course was uneventful
and the patient was discharged from hospital on September 10. At discharge, the WBC count was 6200/mm3 and
CRP was 0.17 mg/dl. The volume-rendered image generated by multidetector row CT showed that the aortic root
was replaced by the homograft and that the coronary bypass grafts were patent (Figure 2). The patient has been
regularly followed up as an out-patient for > 2 years during which he has remained free of infection.
Discussion
Prosthetic valve endocarditis is an incremental risk factor for operative mortality in patients with all types of infective endocarditis. Among them, composite valve-graft
endocarditis after aortic root replacement is supposed tobe the most lethal, because re-operative aortic root replacement itself is associated with high mortality, andperiannular tissue destruction, annular abscess or pseu-Keio J Med 2008; 57 (2): 111－ 114

Fig. 2 Volume rendered image generated by multidetector row
CT. Image shows aortic root replacement with homograft andpatent coronary bypass grafts.

doaneurysms are almost always present. Proper selectionof antibiotics is very important, but this alone is not always sufficient. These difficulties can be overcome bydebriding all infected and necrotic tissues and replacing
the aortic root in addition to prolonged antibiotic therapy.3 According to the guidelines,4 VCM and aminoglycosides comprise the recommended antibiotic combination
for treating prosthetic valve endocarditis when the targeted pathogen is undetectable or undetermined, because
staphylococcus is the most likely culprit. However,gram-negative organisms are also major (>10%) pathogens in this setting. Obviously, targeted antibiotic therapy should be started as soon as the responsible microorganism is detected. We used TEIC for the entire periodof both empiric and targeted antibiotic therapy according
to policy guidelines. Uncontrolled infection is a majorindication for surgical intervention as well as congestive
heart failure and thrombotic events. However, to judge
whether an infection could be controlled with antibiotic
therapy alone, or if surgical intervention is necessary, isdifficult to judge, especially during the early phase. The
timing of surgery tends to be delayed, although early surgical intervention can improve the overall prognosis ofactive infective endocarditis. Surgery is recommendedwhen infection is uncontrolled despite antibiotic administration for 3 to 10 days. Annular abscesses and pseudoaneurysm formation are also strong indications for surgical intervention. From these viewpoints, earlier surgery
might be a viable choice if a homograft is readily available. Possible graft materials for re-replacement include
composites containing mechanical valves,3 freestyle
stentless valves5 and homografts.6 Some authors havefound that prosthetic root replacement as well as homografts result in an excellent long-term outcome7 and thatcomposite graft replacement might be superior to homografts.8 However, homografts are generally believed tobe the optimal material for prosthetic valve endocarditis
because the risks of residual/recurrent infection and ofparavalvular leakage are lower.9-11 Although we also be-113

lieve that homografts are optimal for aortic root re-replacement to treat composite valve-graft endocarditis,
drawbacks include short supply, early calcification insome patients and progressive deterioration. We had access to an appropriately-sized cryopreserved homograft.
During repeat aortic root replacement, unplanned coronary artery bypass grafting constitutes a major risk factor
for hospital mortality. Coronary ostia reimplantation(Carrel patch method) or a second smaller tube graft interposition1 2, 1 3 were not options for coronary reconstruction in our patient because debridement completely
destroyed the coronary ostia. Conventional coronary artery bypass grafting with proximal coronary artery ligation was considered to be the most expedient and safest
route under these circumstances. The patient remains under close observation for late graft atherosclerosis, coronary ischemia and recurrent infection.
The homograft for this patient was provided thanks to
the timely action of the staff of Sapporo Medical College, to whom we are extremely grateful. A network
should be established to acquire and distribute homografts as soon as possible.
Conclusions
Repeat aortic root replacement using a cryopreserved
aortic homograft was successful in a patient with active
composite valve-graft endocarditis.
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